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I noticed that congestion the other day when I was coming back to town... mid-afternoon it was backed up. I'm usually leaving around 5 or 6 if I am heading out of town so I didn't notice the lane reduction. I guess if I gotta head out of town during the day I'll be taking the back way over to Townline road instead, I can't stand sitting in traffic.

(05-08-2016, 03:28 PM)jamincan Wrote: You're supposed to use the entire lane, it's called a zipper merge and actually leads to traffic moving more efficiently.

But there is always that one guy (gal) who drives down the middle of both lanes because they don't think you should be passing on the right.... I've always been a believer that we paid for that asphalt, we should be using it. There was a poll in the Record a few years back where about 50% of drivers think its OK to use the entire lane, and 50% think you should be merging way back and your a jerk for bypassing the stopped traffic....

(05-08-2016, 03:28 PM)jamincan Wrote: You're supposed to use the entire lane, it's called a zipper merge and actually leads to traffic moving more efficiently.

But there is always that one guy (gal) who drives down the middle of both lanes because they don't think you should be passing on the right.... I've always been a believer that we paid for that asphalt, we should be using it. There was a poll in the Record a few years back where about 50% of drivers think its OK to use the entire lane, and 50% think you should be merging way back and your a jerk for bypassing the stopped traffic....

Coke

The correct way to behave in a merge is to match speed with the other lane. Pick a car in the other lane and drive next to it. Ok, don’t drive precisely next to it — drive where you can be seen most effectively. But the point is to force both lanes to run at the same speed. This way, you aren’t merging early (incorrect behaviour), but you also aren’t jumping the queue (also incorrect behaviour). When you get to the proper merge point, you will likely have no trouble executing the merge because the people you’ve been driving next to will understand what you’re doing.

If enough people started doing this, the effect at some point would be to change the dynamic of the merge from “one lane wins” to a symmetric merge.

It would help of course if correct signage were used, which it is not. These are always signed as either left lane merges into right or right into left. Instead, signs that are the mirror image of each other should be used to indicate that both lanes merge into each other with neither lane having priority. This could be indicated in paint by having the dividing line between the lanes split into two dividing lines which would then split apart to meet the outside lines coming together as they reduce from being two lanes apart down to one lane apart. Then everybody has to cross a dashed line which further reinforces that everybody has to take note of the traffic in the other lane.

This doesn’t cover every situation. For example, what about a merge from 3 lanes down to 2? Or on a highway where a lane doesn’t end, but instead exits. But by far the most common case is a simple reduction from 2 lanes to 1.

I've done a lot of reading and debating about this for a long time now, and I believe the general consensus is that its not particularly more efficient from a throughput at the bottleneck point of view. As in, most of the time the reason there's a big long line of cars is that there's a bottleneck ahead that can't support that many cars - and so a line forms. The shape/dynamics of that line don't generally have a significant affect on how many cars get through the bottleneck.

BUT, there are a whole crapload of benefits to the zipper merge:

* It's way more fair. If everyone did it, there's no legal way for somebody at the back to jump forward a significant number of cars.
* Being more fair leads to a decrease in road rage incidents. People don't have to sit there fuming while they think they're being polite and getting in line while others are being 'rude' and jumping to the front.
* It's way more efficient for other non-related traffic. It's not as relevant in the case we're talking about, but in other cases one long single line of cars can have a much larger impact on other non-related traffic (blocking side roads, previous intersections, etc.) than a half/length double wide line of cars.
* There are less accidents. Merging happens at a single point in a defined way where everybody expects it to happen.

From a safety standpoint, you want only one lane to be executing lane changes at once. Both at the same time is a good way to create collisions.

I _love_ ijmorlan's "keep pace" suggestion. It will probably induce your opposite number in the continuing lane to open up a space for you ahead of when you need to merge, which will reduce turbulence and could increase speed for the entire flow. I think I might totally need to try this now.

(05-10-2016, 08:50 AM)SammyOES Wrote: The problem with the 'keep pace' solution is that it effectively just moves the bottleneck point backwards. You get all of the same problems, but earlier.

You also miss a lot of the benefits like 'reduced road rage' because people (rightfully, imo) get annoyed at you for blocking a good portion of roadway that is meant to be used.

Keep pace is bad in the context of zipper merge if it means you are lowering your speed in order to match with the 20th car back of the merge with no one in front of you. It's fine if it means you and the other lane are doing roughly the same speed, and both have roughly the same number of cars in front of you leading up to the merge.

(05-10-2016, 08:59 AM)Viewfromthe42 Wrote: Keep pace is bad in the context of zipper merge if it means you are lowering your speed in order to match with the 20th car back of the merge with no one in front of you. It's fine if it means you and the other lane are doing roughly the same speed, and both have roughly the same number of cars in front of you leading up to the merge.

Totally agreed.

Edit: I should add, zipper merge is also bad for small lines. If there's a line of less than say 15-20 cars on the highway its almost always better and safer to just join the end of the line.

Or think of it this way; the point of a zipper merge is to keep yourself moving at highway speed (80-100 when approaching a bottleneck). Once the speed through the bottleneck (30-60) is seen in vehicles not yet at the bottleneck (ie. full merge has occurred ahead of the final merge point), you are best to merge at the point at which this slower speed occurs.

If there's a line of 20 cars leading up to a bottleneck, and the bottleneck and those 20 cars are moving at 50km/h, if you try to jump up to the final merge point, you slow down 20 cars even below the bottleneck speed, just to get a single car in, yours, moving at the bottleneck speed. It's frustrating, but there's almost no chance of taking a situation where people have been merging ahead of the final merge point, and get it to be a zipper merge at the final merge point. To do that, you'd need to fill the empty lane between the current and final merge points, while also speeding up the speed of the cars through the bottleneck so as to allow the two lanes to move quicker than that up to the merge point, while also having the cars which just filled the empty space between current and final merge points actually sit back and let the folks who were in the steady lane go first until they can get their speed and the bottleneck speed up to an accelerated level.

Point is, once a bad behaviour starts (e.g. early merge), it's better to try going with it than correcting it. Usually the best you can do is, to use a football analogy, move the ball a couple yards, and hope that the next guy does the same. A Hail Mary will just make it worse. I'll usually make a game of it during traffic to watch the cars ahead of me accelerating and braking and attempt to find the perfect speed which allows me to feather the accelerator without ever hitting the brakes, smoothing traffic flow behind me, rather than flashing brakes and inevitably further slowing the traffic jam.

"Point is, once a bad behaviour starts (e.g. early merge), it's better to try going with it than correcting it. "

I disagree with this point. Particularly for long-lived bottlenecks like we're talking about here.

You'd pay a 'one-time' price near the start where a relatively small number of cars are inconvenienced (the people that got in line rather than starting a true zipper merge) and after that you get all of the benefits of the zipper merge.

I disagree with this point. Particularly for long-lived bottlenecks like we're talking about here.

You'd pay a 'one-time' price near the start where a relatively small number of cars are inconvenienced (the people that got in line rather than starting a true zipper merge) and after that you get all of the benefits of the zipper merge.

Any time someone jumps to the head of the line, when the early-merged line is moving at the same speed as the traffic through the bottleneck, everyone already in the merge winds up going slower in order to let you in, and then it will pick up until it gets back to the steady-state speed through the bottleneck. None of this moves the useful merge point (where you go from highway speed down to bottleneck speed) any farther forward, even if it creates a secondary, non-useful merge point (where two bottleneck speed lanes merge into one bottleneck speed lane.

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